Use hash-based deduplication for constraints

sterliakov · sterliakov · commit ff26ebf4d7b3 · 2025-07-10T22:34:48.000+02:00
diff --git a/mypy/constraints.py b/mypy/constraints.py
@@ -272,7 +272,7 @@ def infer_constraints_for_callable(
             )
         )
 
-    constraints = [c for i, c in enumerate(constraints) if c not in constraints[:i]]
+    constraints = list(dict.fromkeys(constraints))
     if any(isinstance(v, ParamSpecType) for v in callee.variables):
         # As a perf optimization filter imprecise constraints only when we can have them.
         constraints = filter_imprecise_kinds(constraints)

Original file line number	Diff line number	Diff line change
`@@ -272,7 +272,7 @@ def infer_constraints_for_callable(`
`272`	`272`	`)`
`273`	`273`	`)`
`274`	`274`
`275`		`- constraints = [c for i, c in enumerate(constraints) if c not in constraints[:i]]`
	`275`	`+ constraints = list(dict.fromkeys(constraints))`
`276`	`276`	`if any(isinstance(v, ParamSpecType) for v in callee.variables):`
`277`	`277`	`# As a perf optimization filter imprecise constraints only when we can have them.`
`278`	`278`	`constraints = filter_imprecise_kinds(constraints)`